There has been known a power sensor including a bus bar through which a current flows and a Hall element for measuring a magnetic field, a part of the bus bar being covered with ferrite, and the Hall element being located in a gap of the ferrite as disclosed in Japanese Patent Application Publication No. 2011-017618. Such a current sensor requires the bus bar, the ferrite, and the Hall element to have a fixed (stable) positional relationship. For example, the positional relationship may be fixed by a ferrite cover including a slit corresponding to a width of the bus bar.
Conventional current sensors have a difficulty in reducing a space because a device to which the current sensor is installed needs to have a structure for preventing a fall of the bus bar and a structure for screwing the ferrite cover.